FIELD OF THE INVENTION
The invention relates to a circuit configuration for stabilizing the operating current of a transistor by negative feedback.
Such circuit configurations are described, for instance, in the publication entitled: Elemente der angewandten Elektronik Elements of Applied Electronics!, by E. Bohmer, 9th Edition, Vieweg-Verlag, Braunschweig, Germany, 1994, and are known in the form of parallel negative feedback or series negative feedback.
Examples of negative feedback are described in more detail below with regard to FIGS. 5, 6a and 6b.
With series negative feedback, it is true that better operating current stabilization can be accomplished in the presence of a fluctuating supply voltage or a departure of a current amplification from a rated value. However, it has the substantial disadvantage that a voltage which must additionally be supplied by the supply voltage source drops at the resistor connected to the emitter supply line. However, in view of the prevailing development in electronic devices to ever-lower supply voltages that is undesirable.